1. Industrial Field of Application
The present invention relates to a data processing apparatus for a chromatograph and, more particularly, to a method of correcting a base line.
2. Prior Art
According to Japanese Patent No. 1,385,425 (Japanese Patent Publication No. 61-54181), as methods of correcting a base line of non-separation peaks, there are: (1) the N method, (2) the .theta. method, and (3) the method of merely connecting a base portion by a straight line (non-correction method).
In the N method, the number of peaks (N) is designated, N peaks are collected as one peak, and either a base portion or a trough portion is connected by a straight line (FIG. 3(A)). The base portion is a portion that is judged as not a peak area by using a change amount of signal as an index.
In the .theta. method, an inclination is intentionally loosened when the inclination seems to be too steep in the N method (FIG. 3(B)).
The non-correction method is a most typical method and is effective when the base line is estimated to be like a straight line (FIG. 3C). In addition, there is also a case of correcting a base line by intentionally selecting a forward horizon method (FIG. 3D), a backward horizon method (FIG. 3E), a special processing method of a shoulder peak (FIG. 3F), or the like in accordance with a peak shape of each chromatogram.